This invention relates to the field of data storage and, more particularly, to improvements in apparatus for facilitating the handling and transport of data storage disk, e.g., optical and magnetic hard disks.
The desirability of handling high density data storage disks without contacting their delicate data recording surfaces is manifest. To facilitate the transport of a data storage disk without contacting the data recording surfaces thereof, it is known to dispose the disk in a so-called "disk carrier". Such a device typically comprises a rigid, planar frame, usually rectangular in shape, having a circular therein slightly larger in diameter than the disk diameter. The disk is supported within the circular aperture by a plurality of spring-biased latches which engage the disk at different points along the disk periphery. Prior to use in a disk player/recorder, the disk is released from the carrier by disk-releasing means associated with the disk player/recorder.
In the commonly assigned U.S. Application Ser. No. 923,509 filed on Oct. 27, 1986 in the names of D. J. Stark et al, there is disclosed a disk carrier of the type mentioned above. The carrier frame is composed of several parts which are rigidly coupled to define a generally circular aperture of fixed diameter slightly larger than the data storage disk. The disk is supported within such aperture by a plurality of small tabs which support a disk from both sides over an arc length of about 10.degree. or less, and a pair of movably mounted latches, each supporting the disk at two other locations equally spaced around the disk periphery. Each of the movable latches is spring-biased toward engagement with the disk periphery and each serves to support the disk over an arc length of a few degrees. Prior to use, disk-releasing means associated with the disk player/recorder serves to urge the movable latches away from the disk periphery. By the arrangement disclosed, a disk may be released from the carrier without substantially displacing the disk relative to its intended axis of rotation.
Disk carriers of the above type are advantageous from the standpoint that a relatively small displacement of the movable latches from the disk periphery can readily effect release of the disk from the carrier. However, such carriers may be viewed as disadvantageous from the standpoint that, under certain conditions, they may release a disk prematurely. In order to solve this problem, an improved carrier has been developed. Such carrier is a subject of the commonly assigned U.S. application Ser. No. 208,190 filed on the same day of this application in the names of Roger G. Covington et al. Such carrier comprises two frame members biased towards each other by spring means so that the frame members themselves, rather than small movable latches, releasably hold a data storage disk. By this carrier, the possibility of premature release of a disk is considerably lowered. However, even with such improved carrier, there remains a slight chance of premature release of the disk when the carrier is subjected to a sudden impulse or a shock, or when a strong force is inadvertently applied to the carrier which tends to pull one frame member from the other. Also, even if the carrier frame members are not sufficiently separated to effect disk release any displacement of the frame members from their nominal positions will act to change the relationship between two racks of transport teeth located along the respective lateral edges of the frame members. Such teeth are designed to be engaged by a toothed conveyor mechanism in an automated disk library. This shifting of the racks will produce an undesired skewing of the carrier and eventually result in a jamming of the carrier in the transport mechanism.